Information that is exchanged in a social network environment mainly includes texts and images. Once it is posted by a user on a social network platform, textual and pictorial information is open for browse by friends of this user.
Despite their acceptable performance on information exchange, existing social network platforms are plagued with some technical limitations. Under many circumstances, a user may only check the textual and pictorial information published by his friends, while other information (e.g., location information of the user and his friends) is generally unavailable. Even if the other information is available, such information is normally tied with the posts that include the textual and pictorial information. For example, location information concerning a user's geographical locations is normally unavailable, and if available, is updated only when the user uploads the posted textual and pictorial information. Thus, when a user reads a friend's posts, the user captures geographical locations where the friend was previously located at the time of publishing the posts, and cannot identify where the friend is currently located. As a result, due to the tie between the location information and the posts, the user may have difficulty in tracking current locations of his friends in real time in the social network environment.